Bioequivalence and Bioavailability Forum

Dear Helmut,

❝ Do I recall it correctly that the method was validated in CPD plasma and partial (cross-?) validation (one batch acc/prec) was done with EDTA plasma of unknown origin? Or – more precisely – it wasn’t even clear whether the anticoagulant was EDTA at all?

Correct. That's what he said, if I remember correctly.

❝ Of course it’s bullshit to ‘evaluate’ unknown samples with one anticoagulant (EDTA) based on calibrators/QCs with another (CPD). All the points you mentioned above might cut in. But this does not speak against CPD as such (I got this impression from your post’s subject line).

If you compare heparin, EDTA and CPD plasma, CPD is certainly the one showing the more difference from the other two. If a lab disregards the EMA guideline, or is working for other markets, and wants to prepare CCs and QCs in a different anticoagulant because they can obtain it more easily, CPD is the worst choice you can get if the subject samples were collected on another anticoagulant.

❝ If a method is validated with any given anticoagulant I would be happy to defend it against an inspector. What arguments would he/she have? “CPD is uncommon; I have seen only methods for this drug with EDTA until now.”

Agreed. If the subject samples were collected on CPD, then the CCs and QCs should be prepared on CPD plasma - with the same proportion of buffer as in the vacutainers during blood collection...

Regards
Ohlbe